The present invention relates generally to the interconnection of control devices and push-pull control cable assemblies. As such, the present invention relates to the interconnection by which a control device actuates the core of a push-pull control cable assembly with respect to the casing thereof. Specifically, the present invention relates to an improved construction for selectively connecting and disconnecting a control device to the core and casing of a push-pull control cable assembly.
Although the prior art shows many constructions for push-pull control cable casings, one of the most suitable constructions, and one which assures greatest flexibility and efficiency, comprises a plurality of wires laid contiguously in a long pitch helix around the outer periphery of a plastic tube, or liner. The helically arranged wires of the casing are maintained in their proper position solely by a plastic cover in the smaller cable and by a reinforcing, spread helix of wire or flat metallic ribbon, in conjunction with the plastic cover, in larger cables.
The plastic tube which comprises the innermost element of the cable casing acts as a bearing for the core of the cable which is slidable within the casing and also acts to protect the casing wires from the elements having access to the interior of the tube. The plastic cover, which comprises the outermost element of the cable casing, not only acts as a structural member to retain the casing wires in their helically coiled configuration but also acts as a protective member to shelter the wires from the exterior elements.
In push-pull control cable installations the ends of the casing are generally clamped in position by end fittings which are either swaged or clamped onto the cable casing. An attaching means is generally provided on the fittings for attaching the casing to an anchoring point.
Normally, an extension tube is swivally mounted to the fitting and the extension tube slidably receives an end rod which has been swaged, or otherwise substantially permanently connected, to the core. As such, the prior art connection between the push-pull control cable assembly and the mechanism which operates, or is operated by, the push-pull control cable is not subject to facile assembly or disassembly once the control device is joined to the push-pull cable assembly, the connection is relatively permanent. Moreover, the type connection heretofore employed generally requires more sophisticated equipment than is generally available for on-the-spot, field installations.
The substantially permanent nature of the prior art connection between a control device -- either the device which controls or the device which is controlled -- and its associated push-pull control cable assembly required that the rather expensive control devices be stocked in conjunction with a variety of push-pull control cable lengths in order to satisfy various installation requirements. Such an arrangement also required that the conjoined control device and push-pull control cable both be removed and installed simultaneously. This, of course, was a major drawback when only one or the other required replacement. Moreover, the direction in which the push-pull control cable assembly was installed was determined by the mounting requirements of the control device attached thereto. For example, if a control device was to be mounted through an opening in a relatively fixed assembly, such as a panel or dash, the entire push-pull cable assembly had to be threaded through the opening in order to mount the control device therein.